Interactive technology use (e.g., Internet and video games) can promote children's educational access and achievement. However, excessive technology use, particularly for entertainment, may adversely affect children's educational development. This study examined the relationship of the amount of entertainment-related interactive technology use and school engagement and performance using two-wave survey data collected from a nationally-representative sample of middle school students in China (N = 9,949, 48% girls, Mean age = 13.5 years). Results showed that nearly 40% of children used interactive technology for entertainment/non-schoolwork-related activities on school days, and, 62%, for entertainment/non-schoolwork-related activities on weekends. Multilevel mixed models revealed that excessive use of technology for entertainment/non-schoolwork-related activities (i.e., 1+ hours on a school day and 4+ hours daily on weekends) was significantly, adversely associated with all outcomes one year later, including lower test scores on Chinese, Math, English, and cognitive competencies, lower educational aspirations, and higher likelihoods of truancy, lacking concentration in class, and boredom at school. Potential reasons for the findings as well as their implications for research and intervention are discussed. Findings will inform the development of feasible and effective guidelines to help parents, teachers, and schools regulate interactive technology use among school-aged children.